content: /*
   * @(#)DoubleViewManager.java
   *
   * Copyright 2002 EGANTT LLP. All rights reserved.
   * PROPRIETARY/QPL. Use is subject to license terms.
   */
  
  package com.egantt.drawing.view.manager;
  
  import com.egantt.drawing.view.ViewManager;
  
  import com.egantt.model.drawing.DrawingAxis;
  
  import com.egantt.model.drawing.axis.AxisView;
  
  import com.egantt.model.drawing.axis.interval.DoubleInterval;
  
  public class DoubleViewManager implements ViewManager
  {
  	protected AxisView view;
  	protected double center = Double.MAX_VALUE; /** treat MAX_VALUE as null */
  	
  	// __________________________________________________________________________
  	
  	public void setView(AxisView view)
  	{
  		this.view = view;
  	}
  	
  	// __________________________________________________________________________
  	
  	public DrawingAxis getAxis()
  	{
  		return view.getAxis();
  	}
  
  	public AxisView getView()
  	{
  		return view;
  	}
  	
  	// __________________________________________________________________________
  	
  	public boolean setStart(Object start)
  	{
  		DoubleInterval visible = (DoubleInterval) view.getInterval();
  		
  		double startValue = ((Double) start).doubleValue();
  		double range = ((Double) visible.getRange()).doubleValue();
  		
  		// update the mid point
  		this.center = startValue + (range / 2);
  		
  		return view.setVisible(new DoubleInterval(startValue, startValue + range));
  	}
  	
  	public boolean setFinish(Object finish)
  	{
  		DoubleInterval visible = (DoubleInterval) view.getInterval();
  		double finishValue = visible.getFinishValue();
  		double range = ((Double) visible.getRange()).doubleValue() / 2;
  		
  		// update the mid point
  		this.center = range / 2;
  		
  		return view.setVisible(new DoubleInterval(finishValue - range, finishValue));
  	}
  	
  	// __________________________________________________________________________
  	
  	public boolean translate(int x, boolean force)
  	{
  		DoubleInterval visible = (DoubleInterval) view.getInterval();
  		double range = visible.getRangeValue() /2;
  		
  		this.center = (center == Double.MAX_VALUE)
  			? range + visible.getStartValue(): this.center;
  		
  		double offset = (range / 50) * x;
  	
  		double startValue = center - range - offset;
  		double finishValue = center + range + offset;
  		
  		if (force)
  		{
  			DoubleInterval interval = (DoubleInterval) getAxis().getInterval();
  			double s = interval.getStartValue();
  			double f = interval.getFinishValue();
  			
  			finishValue += (s > startValue) ?  s - startValue : 0;
  			startValue -= (finishValue > f) ? finishValue -f : 0;
  						
  			startValue = Math.max(startValue, s);
  			finishValue = Math.min(finishValue, f);
  		}
  		return view.setVisible(new DoubleInterval(startValue, finishValue));
  	}
  }
  